A recently developed optical video and/or audio disc player is adapted to play a recording medium in the form of a disc having thereon a helically wound train of discrete pits or the like representing video and/or audio information.
In order to pick up the information on the recording disc, the player has an optical pickup device which has a light source for generating a plane-polarized light beam to be directed toward the recording disc, and a photosensor for detecting the light originated from the light source and reflected from the recording surface of the recording disc. A polarizer prism is provided between the photosensor and the recording disc for deflecting the light from the light source toward the recording disc and passing therethrough the light reflected from the recording disc. A quarter wave plate is provided between the polarizer and the recording disc.
In a prior art optical pickup device of the abovementioned type, the light source means including a light emissive element and a concentrating lens must be situated largely apart from the path of light reflected from the recording disc to the photosensor and thus is so disposed as to project transversely to a considerable extent from the linearly disposed assembly constituted by the quarter wave plate, the polarizer and the photosensor. Therefore, the above-mentioned pickup device has a drawback that it has a considerably large dimension and requires a large space in the pickup device. In addition, the propagation direction of the light from the light source toward the polarizer is perpendicular to the propagation directions in the assembly of the three parts, namely, the wave plate, the polarizer and the photosensor, with the deleterious result that errors of mounting of the polarizer cause the reflecting angle to deviate and degrades the pickup characteristic of the device.